Stable aqueous emulsions



United States Patent M 3,488,312 STABLE AQUEOUS EMULSIONS Eugene S. Barabas, Watchung, and Frederick Grosser, Midland Park, N.J., assignors to GAF Corporation, a corporation of Delaware No Drawing. Filed Nov. 17, 1966, Ser. No. 595,030 Int. Cl. C08f 1/13, 19/00 US. Cl. 260-29.6 3 Claims ABSTRACT OF THE DISCLOSURE Water-insoluble graft terpolymers of a polymerized N-vinyl lactam, such as polyvinyl pyrrolidone, with vinyl acetate and vinylstearate are prepared in stable aqueous emulsions.

The present invention relates, in general, to stable aqueous emulsions and, in particular, to stable, aqueous emulsions comprising a grafted polymeric N-vinyl lactam containing vinyl-acetate and vinylstearate.

Grafted polymers comprising a basic homopolymer chain containing grafted thereon units or a plurality of such units of one or more polymerizable monomers, in chain form, grafted onto the basic homopolymer chain represent an interesting and important development in the resin arts, particularly since such grafted polymers find immediate and practical utility for the resin chemist to utilize them as building block resin systems or module resin systems which can be employed to tailor-make subsequent resin systems to suit specific industrial needs. Grafted copolymers can be made by a variety of polymerization methods including solution, emulsion or bulk polymerization and the like. In the case of polymeric N-vinyl lactams, and particularly polyvinyl pyrrolidone (poly-l-vinyl-2-pyrrolidone), their use has been limited to a great extent to those fields of utility which take advantage of the inherent physical characteristics of polyvinyl pyrrolidone, the most important of which is its water solubility. While this physical characteristic of water solu-' bility has projected polyvinyl pyrrolidone into a position of prominence for such industrial applications as pharmaceutical, cosmetic, textile, lithographic uses, it conversely precluded their use in industrial applications where waterinsolubility of the resin system is a prerequisite.

Accordingly, it is an object of this invention to provide water-insoluble compositions based on polymeric N-vinyl lactams.

Another object of this invention resides in the provision of stable aqueous emulsions of N-vinyl lactams.

Yet another object of this invention resides in the provision of stable aqueous emulsions comprising a grafted polymeric N-vinyl lactam containing vinylacetate and vinylsterate.

Still another object of this invention resides in the provision of stable aqueous emulsions comprising a grafted polymer of polyvinyl pyrrolidone containing vinylacetate and vinylstearate.

Still other objects of the inventions will become further apparent as the description of the invention proceeds.

In accordance with the above-defined objects, methods have been devised whereby stable aqueous emulsion latices are provided comprising N-vinyl lactam containing vinylacetate and vinyl-stearate.

As a result of the invention upon which the present 3,488,312 Patented Jan. 6, 1970 rdiscovery is based, the latices of the present invention find immediate and practical applicability for use as cast films which are transparent, colorless and flexible. The films which are deposited are strong and clear and can be produced directly upon evaporation at room temperatures. Such materials at eminently useful as protective coatings, impregnants and permanent sizing agents for paper, leather and the like. Still other useful applications of the emulsions of the invention include their use as pastes or dispersions in hot dip coating, slush casting and cellular elastomer applications.

The polymeric N-vinyl lactams utilized in the preparation of the compositions of this invention are characterized by the following general structural formula:

L CH 0112-]n wherein R represents an alkylene bridge group necessary to complete a 5-, 6- or 7-rnembered heterocyclic ring system, R represents either hydrogen or an alkyl group, and n represents a number indicative of the extent of polymerization.

All of the specific polymeric materials characterized by the foregoing general formula are commercially available and called polymeric N-vinyl lactams. They are obtained by polymerizing organic 5-, 6- or 7-membered ring compounds containing in their rings the NH-CO-group, such as, for example, 1-vinyl-2-pyrrolidone, l-vinyl-S- methyl-Z-pyrrolidone, 1-vinyl-2-piperidone, N-vinyl-e-caprolactam, and the like. Depending upon the extent of polymerization, polymers having molecular weights ranging from at least 400 up to 2,000,000 or more may be produced. Viscosity measurements are commonly used as an indication of the average molecular weight of polymeric compositions, the instant polymers being characterized by a chain of carbon atoms to which the lactam rings are attached through their nitrogen atoms:

The K value (Fikentscher) of any particular mixture of polymers is calculated from viscosity data and is useful as an indication of the average molecular Weight of such mixture. Its determination is fully described in Modern Plastics, 23, No. 3, 157-61, 212, 214, 216, 218 (1945), and is defined as 1000 times k in the empirical relative viscosity equation:

wherein C is the concentration in grams per hundred cc. of polymer solution and "ML is the ratio of the viscosity of the solution to that of pure solvent. The K values are reported as 1000 times the calculated viscosity coefiicient in order to avoid the use of decimals. For the purpose of the present invention, there may be employed those polymeric N-vinyl lactams having a K value of about 10 to 200, preferably of 30 to because of their viscosity at lower concentrations.

K values and specific viscosities (1 are interconvertible and are related through relative viscosity (1 3 Thus, when viscosity measurements are taken on solutions which have a concentration of 1.00 gram of polymer per deciliter of solution at 25 C. (C=l), the relation ships are as follows:

in admixture dropwise to the reaction mixture or add separately dropwise and at such rate that the respective monomers are completely added at the end of any slated time period. After completion of the addition of all of the monomers, the reaction mixture is then heated for a nrelzflspi'l 5 period up to several hours or more on a steam bath The Relative viscosity=specific viscosity plus one. resulting stable aqueous emulsion contains the resinous interpolymers, above-defined, 1n the form of small par- Relatlve Vlscosity ticles or beads measuring in diameter about from 100 to )l to 300 millimicrons. If desired, an activating agent such as H an alkali metal sulfite or bisulfite, e.g., sodium, potassium, ence etc., sulfites and metabisulfites can be added to the polym- =1+1O[0-001K+0-0O0075K2/(1+0-0015K)1 erization initiator in which case lower polymerization Relative viscosity, specific viscosity and K are dimentemperatures y h used Chalh regulators Such as y sionless, whereas inherent viscosity (log n C and 15 cetyl, dofiecyl, y y h mefcaptflhs can also be f intrinsic viscosity (the limit of inherent viscosity as C ap P Y m the polymFnzatlons- Smtable surface'acnve proaches zero) have the dimensions of dilution, i.e., the agents Fichlde fatty and Soaps faity alcohol sulfates such reciprocal of concentration. Intrinsic viscosity and K are as Sqdmm lauryl Sulfate, hotasslunl 1au ry1 Sulfate intended to be independent of Concentration alkah metal salts of aromatic sulfomc acids, e .g sodium The number of recurring polymer units enclosed bV isobutylnaphthalene sulfonate, etc., sulfosuccinic esters, brackets in the foregoing general structural formula, indi- Phosphate es ters of Polyethoxy alkylPhenols m cated by n, or the extent of degree of polymerization, IHOPTOPY}, dimethyl fi'hydmxyethyl ammonium chlonde corresponds to a chain of roughly 4 to 20,000 monomer and the h h unit-s or more. In actual practice, a mixture of polymeric h emulslons can compounded Y a suc molecules, each containing a different number (n) of Plgments, a wetm 1g agents msms waxes and t monomer units, is always produced. The polymers are f t pr9vldmg a Spectrum of Products havmg readily prepared by the procedural steps given in United Wlde mdusmal apphcaton' States Patents 2,265,450; 2,317,804; and 2,335,454 and It has also been found that stable emulsions of the in which working examples of all the species characterized class F P above can be pliepared W the by the above formula are given and an of which are of emulsifylng agents or protective colloids, although it cotporated herein by reference to Said patents has been observed that it is preferable to add such ma- Whfle not wishing to be bound by any particular theory terials to the emulsion recipe in order to obtain high con- Or mechanism of reaction it is believed that the atrangc versions and greater stability of the resultant emulsions. ment of the monomeric units, that is, the vinylacetate The follo wmg ,example W111 serve to Illustrate the and vinylstearate monomers is an essential part of the H0: of the mventlon: invention in relation to the polymeric N-vinyl lactam. With respect to the interpolymers of the present inven- EXAMPLE I units Vinylacetate h vlhylsteal'ate are not Into a four-necked, one liter resin kettle equipped with Situated 111 the main p ly h chalh h rather y form a 40 a mechanical stirrer, thermometer for liquid temperature, less ahefhahhg S1de chalh 011 the p h dropping funnel, reflux condenser, gas inlet tube and P y y Plfh Whlch forms thfi Skeletal Chalh sampling tube were placed water, polyvinyl pyrrolidone, for the addltion of the vlnylacetate and vinylstearate 1 and ammonium er lf t i the uhltst amounts reflected in Table I and maintained at a tempera- The ratio of the polymeric N-vinyl lactam d t ture of C. Subsequently, vinylstearate and vinylacecomonomers can be 10/90 to 99/1. The ratio of vinyltate monomer were added dropwise over the time increacetate and vinylstearate can be 1/99 and 99/1. For the ments indicated in Table I, as well as subsequent additions preparation of the emulsions of our invention the polymof ammonium persulfate as indicated.

TABLE I Amount S (1 M1. oi Ingredients Added at-Hours of Reaction ee Gm M1. ml. 0 1% 2 3% 4 5 24 25 28 Ingredients:

Water PVP/K-30 vinylstearate Vinylaeetate. (NH4)2S208 1 90.0 grams.

3 10% water solution.

Analysis:

Total solids, percent=33.4. Conversion, percent=95.8. Brookfield visc. (cps.)=75,0.

1 The amount of water for making catalyst solution is deducted.

EXAMPLE II Into a four-necked, one liter resin kettle equipped with a mechanical stirrer, thermometer for liquid temperature, dropping funnel, reflux condenser, gas inlet tube and sampling tube were placed water, polyvinyl pyrrolidone, in the amounts reflected in Table II. Subsequently, vinyl to the desired temperature, and then add the monomers acetate and vinyl stearate monomers were added dropwise 6 polymer in which vinylacetate and vinylstearate comonomers are grafted onto a polymer of an N-vinyl lactam corresponding to the formula:

| C H-CHz L .1 wherein R represents an alkylene bridge group containing from 2 through 4 carbon atoms, R represents a mem- TABLE II Amount Seed Ml. of Ingredients Added atHours of Reaction Gm M1. m1. 0 5 2 3% 4 5 29 48 Ingredients:

02 202 Temperature, 0

1 The amount of water used for making solutions was deducted. 1 Solution in water Analytical Results:

Solids, percent=37.0.

Conversion, percent=94.4.

Brooktield vise. (cps) =481.0.

average molecular weights as determined by the Osmometric Method (H. P. Frank and G. B. Levy, J. Polymer Sci. 10, 371 (1953)) of from about 10,000 in the case of PVP K15 to about 360,000 in the case of PVP K90, PVP K having an average molecular weight of about 40,000 and PVP K having an average molecular weight of about 160,000.

Reference in the specification and claims to parts, proportions and percentages, unless otherwise specified, refer to parts, proportions and percentages by weight.

Since it is obvious that numerous changes and modifications can be made in the above-described details without departing from the spirit and nature of the invention, it is to be understood that all such changes and modifications are included within the scope of the invention and that the invention is not limited to the exemplary details set forth by way of example, except as set forth in the appended claims or as necessitated by the effect of the prior art.

What is claimed is:

1. A stable emulsion comprising water and a graft ter- References Cited UNITED STATES PATENTS 2,890,199 6/1959 McNulty et al 26029.6 2,922,768 1/1960 Mino et al 260-875 X 3,214,498 10/1965 Bauer 260-885 X 3,301,808 1/1967 Mack et al 26029.6

MURRAY TILLMAN, Primary Examiner H. ROBERTS, Assistant Examiner US. Cl. X.R. 

